Management of Syndesmotic Widening with Avulsion Fractures
Surgical fixation is strongly recommended for syndesmotic widening measuring 5.5 mm with associated avulsion fractures to restore ankle stability and prevent long-term morbidity and functional impairment. 1
Assessment and Classification
The patient presents with:
- Mildly displaced avulsion fracture of anterolateral tibial articular surface at AITFL attachment
- Borderline syndesmotic widening (5.5 mm)
- Small undisplaced chip fracture of lateral talus at ATFL attachment
- Ankle and subtalar joint effusion
This represents a grade 2-3 syndesmotic injury with associated avulsion fractures, indicating significant ligamentous disruption.
Treatment Algorithm
1. Surgical Management
- Primary recommendation: Surgical fixation is indicated for syndesmotic widening ≥5 mm with associated avulsion fractures 1
- Surgical options include:
- Syndesmotic screws (metallic or bioabsorbable)
- Dynamic fixation devices (TightRope or ZipTight)
- Hybrid fixation combining suture-button device with syndesmotic screw for complex cases 2
2. Specific Surgical Considerations
- Anatomic reduction is critical - malreduction leads to poor outcomes
- For avulsion fractures:
- Fixation of the anterolateral tibial avulsion fragment if >2 mm displaced 3
- Address the talar avulsion during the same procedure
3. Post-Surgical Protocol
- Non-weight bearing for 2-4 weeks
- Partial weight bearing at 4-6 weeks 2
- Full weight bearing typically by 6-8 weeks
- Early range of motion exercises to prevent stiffness
- Progressive strengthening and proprioception training
Rationale for Surgical Management
Surgical management is preferred over conservative treatment for this presentation because:
- The 5.5 mm syndesmotic widening exceeds the normal anatomic threshold (normal is <5 mm)
- The presence of avulsion fractures indicates significant ligamentous disruption
- Untreated syndesmotic injuries lead to chronic ankle instability, early arthritis, and poor functional outcomes 4
- Surgical fixation shows superior outcomes in restoring ankle stability and function 5
Expected Outcomes
With appropriate surgical management:
- Mean American Orthopaedic Foot and Ankle Society (AOFAS) scores of 86-97 can be expected 5, 3
- Return to full weight-bearing typically occurs at 4-6 weeks post-surgery 5
- Low complication rates (typically <15%) 5
Potential Complications and Prevention
- Malreduction: Use intraoperative fluoroscopy and/or CT to confirm anatomic reduction
- Hardware irritation: Consider suture-button devices which have lower removal rates than screws
- Recurrent diastasis: Ensure adequate fixation and appropriate post-operative protocols
- Infection: Prophylactic antibiotics and proper wound care
Follow-up Protocol
- Clinical and radiographic evaluation at 2 weeks, 6 weeks, 3 months, and 6 months
- Assess for:
- Maintenance of reduction
- Fracture healing
- Ankle stability
- Range of motion
- Functional recovery
Surgical management of syndesmotic injuries with associated avulsion fractures provides the best opportunity for anatomic healing, restoration of ankle stability, and optimal functional outcomes when compared to conservative management in cases with significant displacement.